Electro-active lenses with raised resistive bridges

ABSTRACT

Resistive bridges can connect many ring electrodes in an electro-active lens with a relatively small number of buss lines. These resistors are usually large to prevent excessive current consumption. Conventionally, they are disposed in the same plane as the ring electrodes, which means that the ring electrodes are spaced farther apart or made discontinuous to accommodate the resistors. But spacing the ring electrodes farther apart or making them discontinuous degrades the lens&#39;s optical quality. Placing the ring electrodes and resistors on layers separated by an insulator makes it possible for the ring electrodes to be closer together and continuous with resistance high enough to limit current consumption. It also relaxes constraints on feature sizes and placement during the process used to make the lens. And because the resistors and electrodes are on different planes, they can be formed of materials with different resistivities.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a bypass continuation application of InternationalApplication No. PCT/US2016/060784, filed on Nov. 7, 2016, and entitled“ELECTRO-ACTIVE LENSES WITH RAISED RESISTIVE BRIDGES,” which in turnclaims the priority benefit of U.S. Application No. 62/321,501, whichwas filed on Apr. 12, 2016. Each of these applications is incorporatedherein by reference in its entirety.

BACKGROUND

Electro-active lenses can be made by several methods, includingpatterning a series of concentric electrodes of conductive material on afirst substrate, then sandwiching a layer of liquid crystal between thefirst substrate and second substrate opposite the first substrate. Thesecond substrate may have one or more circular patterns of conductivematerial patterned on it, or any other shape to match or exceed the areaof the patterned electrodes, allowing an electrical circuit to be formedthat creates a voltage field between the two substrates. When anelectrical field is applied across the electrodes, the liquid crystalmaterial between the two substrates changes its index of refraction.

By applying a gradient of voltage fields at different electrodelocations on the lens, a gradient of index of refraction may be created,creating a lens. The higher the number of electrodes that are used, thefiner the resolution of gradient of refractive index can be created.This results in a smoother wavefront curvature, and hence provides abetter quality optic.

However, increasing the number the electrodes also increases thecomplexity of the electronics as well as the light-blocking elementsthat supply power to the electrodes, so methods have been developed toallow a small number of power supply lines to apply a voltage gradientacross a larger number of electrodes. In particular, N power supplylines can be used to apply a voltage gradient across M>N electrodes withresistive bridges between the electrodes. In these electro-activelenses, every M/Nth electrode is connected to a power supply line, andthe other electrodes are coupled to each other with resistive bridges.

In conventional electro-active lenses with resistive bridges, theresistive bridges are made in such a manner that the electrode ring isno longer continuous, degrading optical quality. The problem can bepartially solved by fabricating the resistive bridges in the same planeas the electrodes, locating the resistors in between adjacentelectrodes. In some cases, there are additional shortcomings, includingthe use of extremely high resistive materials, which are difficult tomanufacture in a controllable manner, and the need to fill the entiregap between electrodes with resistive material is required to fill alarge area. In general, it is desirable to reduce the gap betweenelectrodes to improve optical performance, but this can exacerbate thedifficulty of manufacturing the resistive components.

SUMMARY

The inventors have recognized that prior-art solutions to the problem ofreducing the complexity of the drive channels in electro-active lenseshave introduced a new problem: excessive power consumption of theelectro-active lenses. Without resistive bridges, a typical lens designmay consume only nano-amperes of electrical current. However, theresistive bridges provide a pathway for the electrical current to flowfrom one drive channel to the others. This extra current flow leads toan undesired increase in the power consumption of the electro-activelens.

The inventors have recognized that increasing the resistance of theresistive bridges reduces this increased power consumption. In somecases, the resistance can be increased by increasing the resistor'ssize. But fitting the larger resistor into the same plane as theelectrodes means that the gaps between the electrodes must be larger,the electrodes must be interrupted, or both for the larger resistor tofit.

Unfortunately, creating a larger, high resistance bridge in such a smallspace very difficult. In addition, interruptions in the electrodes gapsdegrade the lens's optical performance: etching away a portion of theelectrode to make space for the resistive bridge degrades the integrityof the electrodes and hence the optical performance of the lens. Tofurther compound the problem, the gap between electrodes is a dimensionthat should be reduced as much as possible in order to reduce effectsthat degrade optical performance, further increasing the challenge ofincreasing the resistance of the resistance bridges.

Fortunately, the present technology addresses these problems byproviding larger, higher resistance bridges that do not degrade thelens's optical performance. In these designs, the electrodes can remaincontinuous and close together. In addition, there is no need to removeor sacrifice surface area from the electrodes to make room for theresistive bridges.

Embodiments of the present technology include an electro-optic lenscomprising a first substantially transparent substrate, a plurality ofelectrodes disposed on a surface of the first substantially transparentsubstrate, an insulating layer disposed on the plurality of electrodes,and a resistive bridge disposed on the insulating layer. The resistivebridge connects a first electrode in the plurality of electrodes with asecond electrode in the plurality of electrodes via holes patterned intothe insulating layer. In operation, applying a voltage to the firstelectrode via the resistive bridge causes an electro-active material,such as (bi-stable) liquid crystal, to change its refractive index.

The plurality of electrodes may comprise a plurality of concentric ringelectrodes, with the first electrode being a first concentric ringelectrode and the second electrode being a second concentric ringelectrode. In these cases, the first concentric ring electrode can havea constant width.

The plurality of electrodes may be formed a first material having afirst sheet resistance and the resistive bridge may be formed of asecond material having a second sheet resistance higher than the firstsheet resistance.

There may be insulating material disposed between the first electrodeand the second electrode. This insulating layer may span a gap betweenthe first electrode and the second electrode of less than about 3microns.

The resistive bridge can have a resistance of at least about 2.5 MΩ anda length-to-width ratio of about 25:1. The resistive bridge may includenickel, chromium, indium tin oxide, resistive polymer (e.g., PEDOT:PSS),or any combination or alloy thereof.

The resistive bridge can comprise a plurality of resistive segments,with each resistive segment in the plurality of resistive segments beingin electrical communication with a corresponding pair of electrodes inthe plurality of electrodes. The plurality of resistive segments caninclude a first resistive segment with a first width and a secondresistive segment with a second width greater than the first width. Theplurality of resistive segments can also include a first resistivesegment with a first length and a second resistive segment with a secondlength greater than the first length. And at least one resistive segmentin the plurality of resistive segments may have a curved or bent edge.

Embodiments of the present technology also include a method of making anelectro-optic lens. In one example of this method, a plurality ofelectrodes is formed on a substrate. A layer of insulating material isdeposited on the electrodes. Next, a plurality of through holes isformed in the layer of insulating material. Each through hole in theplurality of through holes connects to a corresponding electrode in theplurality of electrodes. A resistive material is deposited on the layerof insulating material and in the plurality of through holes. And theresistive material is patterned to form a plurality of resistors. Eachresistor in the plurality of resistors connects to a correspondingelectrode in the plurality of electrodes. Optionally, a buss line can beformed in electrical communication with the electrodes and resistors.

In some cases, forming the plurality of electrodes comprises forming aplurality of concentric ring electrodes. In these cases, forming theplurality of concentric ring electrodes may comprise forming a firstconcentric ring electrode separated from a second concentric ringelectrode by a gap of less than about 3 microns. Each concentric ringelectrode may have a constant width (with the widths being the same ordifferent among the concentric ring electrodes).

The resistive material may have a sheet resistance higher than a sheetresistance of the plurality of electrodes. It may be patterned to format least one resistor having a resistance of at least about 2.5 MΩ, atleast one resistor having a length-to-width ratio of about 25:1, orboth. In some cases, there may be a first resistor with a first widthand a second resistor segment with a second width greater than the firstwidth. Likewise, there may be a first resistor with a first length and asecond resistor with a second length greater than the first length. Theresistive material may be patterned to form at least one resistor with acurved edge.

Another embodiment includes an electro-active contact lens with a baseoptical element and an electro-active element embedded within the baseoptical element. The electro-active element includes a plurality ofelectrodes, an insulating layer disposed on the plurality of electrodes,and a resistive bridge disposed on the insulating layer. The resistivebridge connects a first electrode in the plurality of electrodes with asecond electrode in the plurality of electrodes via holes patterned intothe insulating layer.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein. It should also be appreciated that terminologyexplicitly employed herein that also may appear in any disclosureincorporated by reference should be accorded a meaning most consistentwith the particular concepts disclosed herein.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The skilled artisan will understand that the drawings primarily are forillustrative purposes and are not intended to limit the scope of theinventive subject matter described herein. The drawings are notnecessarily to scale; in some instances, various aspects of theinventive subject matter disclosed herein may be shown exaggerated orenlarged in the drawings to facilitate an understanding of differentfeatures. In the drawings, like reference characters generally refer tolike features (e.g., functionally similar and/or structurally similarelements).

FIG. 1 shows an electro-active lens without resistive bridges betweenelectrodes.

FIG. 2A shows the electrodes in the electro-active lens of FIG. 1without the electrical connections that supply power to the electrodes.

FIG. 2B shows the electrodes of FIGS. 1 and 2A with buss lines added.

FIG. 3 shows an electrical schematic of an electro-active lens withoutresistive bridges.

FIG. 4 shows an electrical current flow through each of the drivechannels for the electro-active lens shown in FIG. 3.

FIG. 5A shows a plan view of an electro-active lens with in-planeresistive bridges.

FIG. 5B shows a schematic of an electro-active lens with resistivebridges R1 through R9.

FIG. 6 shows a typical electrical current flow through each of the drivechannels for the electro-active lens shown in FIG. 5.

FIG. 7 shows an electro-active lens with 100 kΩ resistive bridges R1through R9.

FIG. 8 shows a current flow of the electro-active lens shown in FIG. 7.

FIG. 9 shows an electro-active lens with 2.5 MΩ resistive bridges.

FIG. 10 shows a typical electrical current flow through each of thedrive channels for the electro-active lens shown in FIG. 9.

FIG. 11 shows a cross section of an electro-active lens with raisedresistive bridges.

FIGS. 12A-12C show different views of the electrodes, resistors, andbuss lines of the electro-active lens of FIG. 11.

FIG. 12D shows a raised resistive bridge with curved bridge segments.

FIG. 12E shows a raised resistive bridge with bridge segments havingvariable widths.

FIG. 13 shows an electro-active contact lens with raised resistivebridges.

FIG. 14 shows a process for making an electro-active lens with resistivebridges disposed on an insulating layer above an electrode layer.

DETAILED DESCRIPTION

This application discloses electro-active lenses, includingelectro-active contact lenses and electro-active intraocular lenses,with electrodes connected with raised resistive bridges. For instance,the resistive bridges can be disposed on an insulating layer about theelectrodes. Placing the resistive bridges and electrodes on oppositesides of an insulating layer offers many advantages over electro-activelenses without resistive bridges and electro-active lenses withconventional resistive bridges. Compared to an electro-active lenswithout resistive bridges, an electro-active lens with raised resistivebridges can support more electrodes with fewer buss lines. And comparedto an electro-active lens with conventional resistive bridges, anelectro-active lens with raised resistive bridges can support ringelectrodes that are both continuous and closer together because theresistors aren't disposed between the ring electrodes. Continuous,closely spaced electrodes offer better optical performance thandiscontinuous or widely spaced electrodes.

A raised resistive bridge can be larger too, which means that it is lesslikely to break when flexed due its larger surface area. A larger raisedresistive bridge also has higher resistance and lower power consumptionas explained below. In a contact lens or intraocular lens, low powerconsumption is especially beneficial because of limited available powerin such a small device and its subsequently small size battery of powerstorage device. These raised resistive bridges enable lower powerconsumption while preserving the optical capabilities that the device'sdesign provides.

In addition, an electro-active lens with raised resistive bridges can befabricated more easily than an electro-active lens with conventionalresistive bridges because raised resistive bridges don't have to be asprecisely sized, shaped, or positioned as conventional resistivebridges. Put differently, a raised resistive bridge can be made withcoarser resolution features because it goes over the electrodes and isnot part of the optical area. As a result, an electro-active lens withraised resistive bridges can be made using simpler lithography or inkjetprinting on flexible surfaces. And because it is on a different levelthan the electrodes, a raised resistive bridge can also be made fromdifferent materials than the electrodes. For instance, the electrodesmay be made from a conductive, transparent material, such as indium tinoxide (ITO), and the raised resistive bridge may be made of a materialwith a higher resistivity than ITO.

Electro-Active Lenses without Resistive Bridges

FIG. 1 shows an exploded, perspective view of an electro-active lens 100without resistive bridges. The electro-active lens 100 includes a lowersubstrate 110 patterned with a set of concentric ring electrodes 205 andconductive connection pads 115. Conductive buss lines 210 connectrespective electrodes 205 with respective conductive connection pads115. The electrodes 205, buss lines 220, and connection pads 115 may beformed of a transparent conductive material, such as indium tin oxide(ITO), that is deposited onto the lower substrate 110 and patternedusing standard lithographic techniques. An upper substrate 130 forms theother half of the lens 110. The underside of the upper substrate 130 iscoated with a layer of transparent conductive material that acts asanother electrode (e.g., a ground plane 135). A layer of liquid crystalmaterial 120 is sandwiched between the upper substrate 130 and the lowersubstrate 120 to form the lens 110.

In operation, the individually controllable voltage at each buss line220 may be utilized to modulate the refractive index of the liquidcrystal material 120 between the corresponding ring electrode 220 andthe ground plane 135. For instances, the voltages applied to the busslines 220 may be selected to generate spherical wave front when the lens100 is positioned in the path of a plane wave. The voltages may also beselected to deviate from a sphere-only wave front. Such a deviation maybe useful in correcting higher order aberrations, one example beingspherical aberration.

FIGS. 2A and 2B show the concentric circular electrodes 205 of theelectro-active lens 100 of FIG. 1 in greater detail. FIG. 2A shows thelens 100 without the electrical connections yet made to supply power tothe electrodes 205. The circular electrodes 205 are typically made froma transparent but electrically conductive material such as indium tinoxide (ITO), patterned on a transparent substrate, such as glass orplastic. Between each electrode 205 is a gap 210 without conductivematerial to prevent electrical connection between the electrodes 205.The gaps 210 (nineteen shown) may be either left unfilled or filled witha non-conductive material, for example, silicon dioxide (SiO₂). In manycases, it is desirable to make this gap as small as possible, withtypical gap sizes of 1 to 3 microns. Smaller or larger gaps are alsopossible. In this example, twenty electrodes 205 are shown, but manymore are typically used, perhaps hundreds or thousands.

The lens 100 may include an insulating layer (not shown) on top of thecircular electrodes 205 and gaps 210. This insulating layer may be madefrom a material that does not conduct electricity but is opticallytransparent, for example, a 125 nm thick layer of SiO₂ deposited overthe electrodes 205. A series of holes 200 (twenty shown) are patternedin the insulating layer to expose a section of each underlying electrode205. The purpose of these holes 200 is explained below with respect toFIG. 2B.

FIG. 2B shows the electrodes 205 with buss lines 220 (twenty shown)connected to respective electrodes 205 via respective holes 200. Busslines 220 are made from an electrically conductive material, forexample, nickel. They are typically about 10 microns wide, but can benarrower (e.g., 1 micron) if space is limited and power conduction islow or wider (e.g., 100 microns) if power conduction is higher. Eachbuss line 220 may be up to 10 mm long, depending on the circuit design.

In operation, the buss lines 220 provide electrical power to theelectrodes 205. Each buss line 220 delivers power only to its designatedelectrode 205 and not to any other electrode 205. The insulating layerprevents the buss lines 220 from shorting out or connecting to the otherelectrodes below it, and only allows connection of the buss line 220 tothe desired electrode 205 through the via hole 200 in the insulatinglayer.

The example lens 100 shown in FIGS. 1 and 2 uses one buss line perelectrode. In this example design of twenty electrodes, providing twentybuss lines and twenty electrical drive channels is manageable, but whenthe lens has many more electrodes, using one buss lines per electrodecan become problematic. Additional buss lines can degrade the lens'soptical quality by blocking light and adding undesired diffractionsources, and every additional electrical channel adds complexity andcost to the electronics. These problems can be mitigated by addingresistors between electrodes, allowing only a subset of the electrodesto be connected to the buss lines. The electrodes that aren't connectedto the buss lines are powered by current delivered via resistive bridgesand adjacent electrodes. This reduces the number of buss lines andelectrical drive channels, but can increase the electrical powerconsumption as described in greater detail below.

FIG. 3 shows a typical electrical schematic of an electro-active lenswithout resistive bridges (e.g., lens 100 in FIGS. 1 and 2). Drivesignals are provided by analog output voltage sources 5, 10, 15, 20, 25,30, 35, 40, 45 and 50. These voltage sources are supplied by acontroller (not shown), such as an application-specific integratedcircuit (ASIC) embedded or electrically coupled to the electro-activelens. Capacitors C1 through C10 on the left side of the schematic inFIG. 3 represent the capacitance created by the liquid crystal layer(not shown) modulated by the electrodes. The ground symbol shows theground plane to be the substrate opposite to thepatterned-with-electrodes substrate as well as the opposite potential ofthe analog outputs.

The drive signal in this example is a square wave oscillating at 100 Hz,with the peak to peak voltage amplitude being, from voltage source 5through 50, 0.57, 0.62, 0.69, 0.76, 0.83, 0.0.92, 1.03, 1.13, 1.27 and1.5 volts, respectively. These voltages are determined by the desiredgradient of retardation in the liquid crystal to create the desiredoptical effect. There is a relationship between the liquid crystalresponse and voltage referred to as the Threshold Voltage, typicallyreferred to as the V10-V90 specification, indicating the voltage rangeneeded to move the liquid crystal molecules through 80% of its range.The voltages may be adjusted to compensate for other design variables,such as the distance from the electrodes to the liquid crystal or theliquid crystal layer thickness.

FIG. 4 shows a typical electrical current flow through each of the drivechannels for an electro-active lens without resistive bridges like thoseillustrated in FIGS. 1-3. The maximum electrical current seen is 120nano-Amperes (120×10⁻⁹ A). If the electro-active lens's controlcircuitry draws another 130 nano-Amperes, this current is low enoughthat the lens 100 can operate for about 40 hours using a 10-microamphour battery, which is small enough to be embedded in an electro-activeophthalmic lens, such as an electro-active contact lens orelectro-active intraocular lens.

Electro-Active Lenses with In-Plane Resistive Bridges

FIG. 5A shows a plan view of electrodes 34 connected by in-planeresistive bridges 38 in a (prior art) electro-active lens from U.S. Pat.No. 9,280,020 to Bos et al., which is incorporated herein by referencein its entirety. The electrodes 34, in-plane resistive bridges 38, and acentral disk electrode 35 are formed by patterning an electrode layer 30on a substrate 22. As shown in a close-up region 2-2, the in-planeresistive bridges 38 span gaps 36 (e.g., open spaces) between adjacentelectrodes 34, making it possible to reduce the number of inputconnections 70 between the electrodes 34 and the voltage source (notshown).

The close-up 2-2 also shows that the in-plane resistive bridges 38create discontinuities, such as variations in width and (sharp) corners,that prevent the electrodes 34 from being perfect rings. If theresistive bridges 38 are large enough, these breaks or discontinuitiescan degrade the electro-active lens's optical performance and theelectrode's electrical performance. Typically, in-plane resistivebridges that deliver good optical performance are typically 2 micronswide and 4 microns long. However, a resistor of this size is only abouttwo squares of resistive material, making it difficult to use materialswith a high enough resistivity or sheet resistance to provide thedesired resistance to keep power consumption low as explained below.Increasing the area increases the resistance, but also necessitates alarger gap between electrodes 34, a larger discontinuity in eachresistor 38, or both. As shown in FIG. 5A, intruding into the electrode34 to lengthen the resistor 38 can provide the area to increase theresistor's length-to-width ratio so a larger amount of resistivematerial can be used, resulting in higher resistance, but the integrityand performance of the electrodes 34 is then compromised. The electrodes38 shown in FIG. 5A are typically 30 microns long and 3 microns wide(about 10 squares), which provides decent resistance but degradesoptical performance.

FIG. 5B shows an electrical schematic of an electro-active lens within-plane resistive bridges R1 through R9. Each of these resistors has aresistance value of 2,000 ohms. These resistive bridges are formed inthe same plane as the electrodes between adjacent electrodes. At thisresistance value, they can have dimensions small enough not to degradethe electro-active lens's optical quality. That is, they are smallenough to fit within the gap between electrodes and do not diffract orscatter enough incident light to obstruct or occlude a user's ability tosee clearly through the lens. But the resistors increase the lens'scurrent consumption dramatically.

FIG. 6 shows the typical electrical current flow through each of thedrive channels for the electro-active lens shown in FIG. 5. The maximumelectrical current is 117 micro-Amperes (117×10⁻⁶ A). At this currentconsumption, the electro-active lens would deplete a 10-microamp hourbattery in about five minutes, which is too short to be practical formost ophthalmic applications.

FIG. 7 shows an electrical schematic of an electro-active lens within-plane resistive bridges R1 through R9 with resistance values of100,000 ohms each. These resistive bridges are larger and thus are morelikely to degrade the lens's optical performance. The increasedresistance cuts the lens's current consumption, but not by enough tomake the lens practical for ophthalmic applications.

FIG. 8 shows the current flow of the lens shown in FIG. 7. Although theresistance is substantial, the peak current consumption is almost 2.5micro-Amperes (2.5×10⁻⁶ A), which is more than twenty times higher thanthe current consumed by the lens without resistive bridges shown in FIG.3. Even at this current consumption level, this electrode/resistorconfiguration would have a battery life that is too short for use incontact lenses or intraocular lenses.

FIG. 9 shows an electrical schematic of an electro-active lens with theresistive bridges modified to each have 2,500,000 ohms of resistance(2.5 MΩ). These resistive bridges are about 50 microns long by 2 micronswide, which is large enough to degrade the electro-active lens's opticalperformance. At this resistance, the electrical current begins toapproach the resistance between electrodes in an electro-active lenswithout resistive bridges in the circuit. But the resistive bridges arealso large enough that the electrodes must be farther apart or bent orcurved for the resistive bridges to fit between them. Pushing theelectrodes farther apart or changing their shape degrades the lens'soptical quality, making the lens unsuitable for many ophthalmicapplications.

FIG. 10 shows the typical electrical current flow through each of thedrive channels for the electro-active lens described in FIG. 9. Themaximum electrical current is 200 nano-Amperes (200×10⁻⁹ A), whichapproaches the level of power consumption of a lens without resistivebridges. The current consumption is low enough for the lens's batterylife to roughly match that of an electro-active lens without resistivebridges, but the lens's optical quality is worse than that of anelectro-active lens without resistive bridges. As result, even thoughthe lens with 2.5 MΩ in-plane resistive bridges has a battery life longenough for use as a contact lens or intraocular lens, it can't be usedas a practical contact lens or intraocular lens.

Electro-Active Lenses with Raised Resistive Bridges

FIGS. 11-12 show electro-active lenses and concentric ring electrodeswith raised resistive bridges and how they may be used in anelectro-active lens. Rather than the resistors being within a gapbetween electrodes or connected at a break point in each electrode,there is an insulating layer between the resistor and the electrodes,which are connected through the vias in the insulating layer. Thisyields continuous electrode rings because there is no need to removesurface area from the electrodes to make room for the resistors. It alsoenables resistors with a larger ratio of length to width. This longerlength-to-width ratio allows the resistors to be fabricated with a veryhigh overall resistance and a smaller sheet resistance. For example, fora material with a sheet resistance of 100 kΩ per square, which is acommon, easily fabricated type of material, the resistor between bussline connection points can have a resistance of 2.5 MΩ with alength-to-width ratio of 25:1. Other resistances and length-to-widthratios are also possible, depending on the resistive bridge material andlens design criteria, which may include desired battery life.

One other advantage of raising the resistive bridges to a level above(or below) the electrodes is that the resistive bridge material can bedifferent than that of the electrodes. This allows the material to beselected for the electrodes that has the desired optical qualities butperhaps low resistance, and a different material selected for theresistors that has high resistance but perhaps low optical quality.Since the resistors comprise such a miniscule area of the lens, they caneven be made of an opaque material without having a meaningful impact onthe lens's optical quality.

FIG. 11 shows a cross section of a portion of an electro-active lenswith a raised resistive bridge (resistor) 350. This resistive bridge 350is electrically connected to several electrodes 305 a-305 e(collectively, electrodes 305), which are patterned onto a substrate310. In an ophthalmic lens, such as a contact lens, there may be tens tohundreds of electrodes 305 spanning a width of about 10-20 mm, with eachelectrode 305 having widths on the order of microns to millimeters(e.g., 0.5 μm, 1 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 100 μm, 250 μm, 500 μm, 1 mm, 1.5mm, 2 mm, or any other value or range up between about 0.5 μm and about2 mm). Depending on the implementation, the electrodes 305 may ofidentical or different widths, possibly with a disc-shaped electrode atthe center of the lens.

Unlike in an electro-active lens with conventional resistive bridges,the electrodes 305 shown in FIG. 11 are each of uniform width, with nodiscontinuities. In addition, the gaps between adjacent electrodes arealso relatively small. For instance, these gaps may range in size fromnanometers to microns (e.g., 100 nm, 200 nm, 250 nm, 300 nm, 400 nm, 500nm, 1 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10μm or any other value or range up to about 10 μm). The electrodes 305may be relatively thin, e.g., less than 200 nanometers (nm), andpreferably less than 40 nm.

An insulating layer 300 is blanketed over the electrodes 305, and bussline via holes 330 a and 330 b (collectively, buss line via holes 330)are patterned into the insulating layer 300. For instance, theinsulating layer 300 may be a 120 nm thick layer of silicon dioxide or a0.5 μm thick layer of SU-8. Resistor via holes 340 a-340 c(collectively, resistor via holes 340) are also patterned into theinsulating layer 300. The resistive bridge 350 is then formed such thatthe underlying electrodes 305 are connected through the resistive bridge350 through the via holes 330 and 340. Buss lines 315 a and 315 b(collectively, buss lines 315) connect through the via holes 330 a and330 b, respectively, to both the resistive bridge 350 and the electrodes305 a and 305 e. Electrodes 305 a and 305 e are powered directly by busslines 315 a and 315 b, while electrodes 305 b-305 d are poweredindirectly through the resistive bridge 350.

The sheet resistance of the resistive bridge 350 may range of fromapproximately 0.1 MΩ per square to approximately 100 MΩ per square ormore. The sheet resistance of the insulating layer 300 is greater thanapproximately 10¹⁸ Ω per meter, and ideally infinite. The resistance ofthe electrodes 305 is less than approximately 200 Ω per square. Othermeasures of resistance may be used depending on the optical effectssought to be achieved. The resistive layer may be relatively thin, e.g.,less than 200 nanometers (nm), and preferably less than 40 nm.

Although FIG. 11 shows the buss lines 315 connecting to resistive bridge350 inside of buss line via holes 330 in such a manner as sharing theelectrode 305, other configurations can be made by those skilled in theart of via hole design. For example, the resistive bridge could occupythe entire bottom of the via hole with the buss line on top of theresistive bridge material. The buss line could also occupy the entirebottom of the via hole with the resistive bridge on top of the buss linematerial. Likewise, the resistive bridge could be connected to more orfewer electrodes.

Having the resistive bridge 350 above the insulating layer 300 providesmore room for resistor construction, allowing higher length-to-widthratios to be used without compromising or interrupting the integrity ofthe electrodes 305. All other things being equal, increasing aresistor's length-to-width ratio increases its resistance. And higherresistance translates to lower current consumption and longer batterylife. A higher length-to-width ratio might not be possible if theresistor had to remain within the gap between the electrodes at theplane of the electrodes.

Placing the resistive bridge 350 above the insulating layer 300 andelectrodes also provides for greater flexibility in material choices forthe resistor's construction and more robust, more forgiving errortolerance when constructing resistors with high resistance. Forinstance, the resistive bridge 350 can made of a transparent conductivematerial, such as indium tin oxide, or a layer of material that is thinenough to be translucent, such as a layer of nickel that is micronsthick. If the resistive bridge 350 is used in a reflection geometry, orif the resistive bridge 350 is relatively small, it can be made of anopaque material (e.g., a thicker layer of metal).

FIGS. 12A and 12B show a plan view of the electrodes 305, buss lines315, buss line via holes 330, resistor via holes 340, and resistivebridge 350. (FIG. 12B is a close-up view.) Buss lines 315 (six areshown) penetrate the insulation layer at buss line via holes 315 in sixlocations, making electrical connection to the electrodes 305. Aresistive bridge 350 is also connected at buss line via holes 315. Theresistive bridge 350 connects to the unpowered electrodes 305 throughresistor-only via holes 340 (fourteen are shown).

FIG. 12C shows the buss lines 315, buss line via holes 330, resistor viaholes 340, and resistive bridge 350 without the electrodes 305. Althoughthe resistive bridge 350 is shown as set of straight line segments (eachof which could be considered as an individual resistive bridge), theycould be other shapes and sizes as well to provide better control of thedesired resistance.

For example, FIG. 12D shows a raised resistive bridge 350′ with curvedbridge segments 352 a-352 d (collectively, curved bridge segments 352)that connect adjacent via holes 330 and 340. In this case, the curvedbridge segments 352 form an undulating or sine-like path between a pairof buss line via holes 330. In other cases, the resistive bridgesegments could take a different non-straight (e.g., curved, twisted, orjagged) path from one via hole to the next. Moreover, each bridgesegment can have a different curvature or path—some can have largerradii of curvature than others or take paths of different shapes. Thiswould increase the length and resistance of each segment and of theresistive bridge as a whole. The curvature may also affect the resistivebridge's other electrical properties, including its inductance,capacitance, or both.

Similarly, FIG. 12E shows a raised resistive bridge 350″ with segments354 a-354 d (collectively, variable-width bridge segments 354) whosewidths vary from segment to segment. In this case, the segments 354bulge in the middle, but other shapes could be used as well. Thisvariation may be used to provide resistors to compensate for variationsin resistance due to length variations among segments of the resistivebridge. The width of each segment may also be varied deliberately tocreate non-uniform resistance values from segment to segment. Forinstance, the segment width may be varied to create a non-linearresistance gradient, such as a parabolic resistance gradient. Thisparabolic resistance gradient could be used to create a parabolicgradient of the electric field resulting in a lens with even fewer busslines (and better optical quality).

An Electro-Active Contact Lens with Raised Resistive Bridges

FIG. 13 shows an electro-active contact lens 1300 with raised resistivebridges 1350. The electro-active contact lens 1300 includes anelectro-active lens element 1302 with an electro-active material, suchas nematic or cholesteric liquid crystal, sandwiched between a pair oftransparent substrates, just like the lens 100 shown in FIG. 1. Theliquid crystal could also be contained within a cavity defined byfolding a single substrate onto itself. One of the surfaces opposite theliquid crystal material is patterned to include a plurality ofconcentric ring electrodes made of transparent conductive material asshown in FIGS. 11 and 12A.

The electro-active lens element 1302 also includes a raised resistivebridge 1350 disposed on an insulating layer as shown in FIG. 11. Thisraised resistive bridge 1350 includes segments that connect theelectrodes to each other and to buss lines 1320, also as shown in FIGS.11 and 12A. The buss lines 1320 connect in turn to a bus 1322, whichconnects to a processor (here, an ASIC 1324) via a flexible printedcircuit board (PCB) 1326. The flexible PCB 1326 also connects the ASIC1324 to a ring-shaped power battery 1328 and a ring-shaped antenna 1330,both of which are concentric with the electro-active lens element 1302as shown in FIG. 13. All of these components are completely or partiallyembedded in a base optical element 1304. This base optical element 1304may provide additional optical power—i.e., it may function as a fixedlens—and can be formed of any suitable material, include soft hydrogelslike those used in soft contact lenses.

In operation, the ASIC 1324 actuates the electro-active lens element1302 in response to signals received by the antenna 1330 or generated byone or more sensors (not shown) embedded in the electro-active contactlens 1300. The ASIC 1324 controls the optical power provided by theelectro-active lens element 1302 by modulating the voltages applied tothe electrodes via the buss 1326, buss lines 1320, and raised resistivebridges 1350. Because the raised resistive bridges 1350 are in adifferent plane than the electrodes, they can be relatively large (e.g.,2.5 MΩ) without degrading the lens's optical performance. At this size,they also limit current consumption to reasonable rates (e.g., on theorder of 100-200 nA), which makes it possible for the battery 1328 to golong stretches (e.g., 40 hours or more) between rechargings (e.g., viathe coil-shaped antenna 1330) or before the electro-active contact lens1300 is thrown away.

Making an Electro-Active Intraocular Lens with Raised Resistive Bridges

FIG. 14 shows a process 1400 for making an electro-active intraocularlens with raised resistive bridges. In step 1402, conductive material(e.g., ITO) is deposited on a transparent substrate, such as a piece offlexible polymer. The electrode material is lithographically pattern toform electrodes (e.g., concentric ring-shaped electrodes) in step 1404.Next, in step 1406, a layer of insulating material, such as silicondioxide, is deposited on the patterned electrodes. Through-holes arelithographically patterned into the insulating layer in step 1408. Instep 1410, resistive material is disposed on the insulating layer and inthe through-holes, forming electrical connections to the electrodes.Suitable resistive materials include, but are not limited to, alloys ofnickel and chromium, ITO doped with oxygen, combinations of metals withoxides, and resistive polymers, such as poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS). The resistive material is patternedlithographically to form raised resistive bridges in step 1412, A layerof conductive material is disposed on the resistive bridges and exposedinsulating layer in step 1414 and patterned to form the buss lines instep 1416.

CONCLUSION

While various inventive embodiments have been described and illustratedherein, those of ordinary skill in the art will readily envision avariety of other means and/or structures for performing the functionand/or obtaining the results and/or one or more of the advantagesdescribed herein, and each of such variations and/or modifications isdeemed to be within the scope of the inventive embodiments describedherein. More generally, those skilled in the art will readily appreciatethat all parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the inventive teachingsis/are used. Those skilled in the art will recognize, or be able toascertain using no more than routine experimentation, many equivalentsto the specific inventive embodiments described herein. It is,therefore, to be understood that the foregoing embodiments are presentedby way of example only and that, within the scope of the appended claimsand equivalents thereto, inventive embodiments may be practicedotherwise than as specifically described and claimed. Inventiveembodiments of the present disclosure are directed to each individualfeature, system, article, material, kit, and/or method described herein.In addition, any combination of two or more such features, systems,articles, materials, kits, and/or methods, if such features, systems,articles, materials, kits, and/or methods are not mutually inconsistent,is included within the inventive scope of the present disclosure.

The above-described embodiments can be implemented in any of numerousways. For example, embodiments of designing and making the technologydisclosed herein may be implemented using hardware, software or acombination thereof. When implemented in software, the software code canbe executed on any suitable processor or collection of processors,whether provided in a single computer or distributed among multiplecomputers.

Further, it should be appreciated that a computer may be embodied in anyof a number of forms, such as a rack-mounted computer, a desktopcomputer, a laptop computer, or a tablet computer. Additionally, acomputer may be embedded in a device not generally regarded as acomputer but with suitable processing capabilities, including a PersonalDigital Assistant (PDA), a smart phone or any other suitable portable orfixed electronic device.

Also, a computer may have one or more input and output devices. Thesedevices can be used, among other things, to present a user interface.Examples of output devices that can be used to provide a user interfaceinclude printers or display screens for visual presentation of outputand speakers or other sound generating devices for audible presentationof output. Examples of input devices that can be used for a userinterface include keyboards, and pointing devices, such as mice, touchpads, and digitizing tablets. As another example, a computer may receiveinput information through speech recognition or in other audible format.

Such computers may be interconnected by one or more networks in anysuitable form, including a local area network or a wide area network,such as an enterprise network, and intelligent network (IN) or theInternet. Such networks may be based on any suitable technology and mayoperate according to any suitable protocol and may include wirelessnetworks, wired networks or fiber optic networks.

The various methods or processes (e.g., of designing and making thetechnology disclosed above) outlined herein may be coded as softwarethat is executable on one or more processors that employ any one of avariety of operating systems or platforms. Additionally, such softwaremay be written using any of a number of suitable programming languagesand/or programming or scripting tools, and also may be compiled asexecutable machine language code or intermediate code that is executedon a framework or virtual machine.

In this respect, various inventive concepts may be embodied as acomputer readable storage medium (or multiple computer readable storagemedia) (e.g., a computer memory, one or more floppy discs, compactdiscs, optical discs, magnetic tapes, flash memories, circuitconfigurations in Field Programmable Gate Arrays or other semiconductordevices, or other non-transitory medium or tangible computer storagemedium) encoded with one or more programs that, when executed on one ormore computers or other processors, perform methods that implement thevarious embodiments of the invention discussed above. The computerreadable medium or media can be transportable, such that the program orprograms stored thereon can be loaded onto one or more differentcomputers or other processors to implement various aspects of thepresent invention as discussed above.

The terms “program” or “software” are used herein in a generic sense torefer to any type of computer code or set of computer-executableinstructions that can be employed to program a computer or otherprocessor to implement various aspects of embodiments as discussedabove. Additionally, it should be appreciated that according to oneaspect, one or more computer programs that when executed perform methodsof the present invention need not reside on a single computer orprocessor, but may be distributed in a modular fashion amongst a numberof different computers or processors to implement various aspects of thepresent invention.

Computer-executable instructions may be in many forms, such as programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc. that perform particular tasks or implement particularabstract data types. Typically, the functionality of the program modulesmay be combined or distributed as desired in various embodiments.

Also, data structures may be stored in computer-readable media in anysuitable form. For simplicity of illustration, data structures may beshown to have fields that are related through location in the datastructure. Such relationships may likewise be achieved by assigningstorage for the fields with locations in a computer-readable medium thatconvey relationship between the fields. However, any suitable mechanismmay be used to establish a relationship between information in fields ofa data structure, including through the use of pointers, tags or othermechanisms that establish relationship between data elements.

Also, various inventive concepts may be embodied as one or more methods,of which an example has been provided. The acts performed as part of themethod may be ordered in any suitable way. Accordingly, embodiments maybe constructed in which acts are performed in an order different thanillustrated, which may include performing some acts simultaneously, eventhough shown as sequential acts in illustrative embodiments.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of” or, when used inthe claims, “consisting of” will refer to the inclusion of exactly oneelement of a number or list of elements. In general, the term “or” asused herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of” or“exactly one of” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

The invention claimed is:
 1. An electro-optic lens comprising: a firstsubstantially transparent substrate; a plurality of electrodes disposedon a surface of the first substantially transparent substrate, theplurality of electrodes comprising a first electrode disposed on thesurface of the first substantially transparent substrate and a secondelectrode disposed on the surface of the first substantially transparentsubstrate; an insulating layer disposed on the first electrode, thesecond electrode, and on a portion of the surface of the firstsubstantially transparent substrate between the first electrode and thesecond electrode; and a resistive bridge disposed on the insulatinglayer over the portion of the surface of the first substantiallytransparent substrate between the first electrode and the secondelectrode, the resistive bridge connecting the first electrode with thesecond electrode via holes patterned into the insulating layer.
 2. Theelectro-optic lens of claim 1, wherein the plurality of electrodescomprises a plurality of concentric ring electrodes, the first electrodeis a first concentric ring electrode, and the second electrode is asecond concentric ring electrode.
 3. The electro-optic lens of claim 2,wherein the first concentric ring electrode has a constant width.
 4. Theelectro-optic lens of claim 1, wherein the plurality of electrodes isformed of a first material having a first sheet resistance and theresistive bridge is formed of a second material having a second sheetresistance higher than the first sheet resistance.
 5. The electro-opticlens of claim 1, wherein the insulating layer on the surface of thefirst substantially transparent substrate comprises: insulating materialdisposed between the first electrode and the second electrode, theinsulating layer spanning a gap between the first electrode and thesecond electrode of less than about 3 microns.
 6. The electro-optic lensof claim 1, wherein the resistive bridge has a resistance of at leastabout 2.5 MΩ.
 7. The electro-optic lens of claim 1, wherein theresistive bridge has a length-to-width ratio of about 25:1.
 8. Theelectro-optic lens of claim 1, wherein the resistive bridge comprises atleast one of nickel, chromium, indium tin oxide, or resistive polymer.9. The electro-optic lens of claim 1, wherein the resistive bridgecomprises a plurality of resistive segments, each resistive segment inthe plurality of resistive segments being in electrical communicationwith a corresponding pair of electrodes in the plurality of electrodes.10. The electro-optic lens of claim 9, wherein the plurality ofresistive segments includes a first resistive segment with a first widthand a second resistive segment with a second width greater than thefirst width.
 11. The electro-optic lens of claim 9, wherein theplurality of resistive segments includes a first resistive segment witha first length and a second resistive segment with a second lengthgreater than the first length.
 12. The electro-optic lens of claim 9,wherein at least one resistive segment in the plurality of resistivesegments has at least one of a curved edge or bent edge.
 13. Theelectro-optic lens of claim 9, wherein each resistive segment in theplurality of resistive segments has a different resistance.
 14. Theelectro-optic lens of claim 9, wherein the plurality of resistivesegments provides a non-linear resistance gradient.
 15. Theelectro-optic lens of claim 14, wherein the non-linear resistancegradient is a parabolic resistance gradient.
 16. The electro-optic lensof claim 1, wherein the resistive bridge is configured to limit currentconsumption by the electro-optic lens to about 100-200 nA.
 17. Theelectro-optic lens of claim 1, further comprising: an input connection,connected to the first electrode, and an output connection, connected toanother electrode in the plurality of electrodes, to power the firstelectrode directly and to power the second electrode via the resistivebridge.
 18. The electro-optic lens of claim 1, wherein the firstelectrode and the second electrode are disposed directly on the surfaceof the first substantially transparent substrate.
 19. A method ofoperating an electro-optic lens comprising a plurality of electrodes,the plurality of electrodes comprising a first electrode disposed on asurface of a substrate and a second electrode disposed on the surface ofthe substrate, the method comprising: applying voltage to the firstelectrode via a buss line connected to the first electrode via a firsthole in an insulating layer disposed on the plurality of electrodes; andapplying voltage from the buss line to the second electrode via thefirst electrode and a resistive bridge spanning a portion of theinsulating layer on the surface of the substrate between the firstelectrode and the second electrode.
 20. The method of claim 19, whereinthe resistive bridge limits current consumption by the electro-opticlens to about 100-200 nA.
 21. A method of making an electro-optic lens,the method comprising: forming a plurality of electrodes on a substrate,the plurality of electrodes comprising a first electrode and a secondelectrode on a surface of the substrate; depositing a layer ofinsulating material on the plurality of electrodes and on a portion ofthe surface of the substrate between the first electrode and the secondelectrode; forming a plurality of through holes in the layer ofinsulating material, the plurality of through holes comprising a firstthrough hole connecting to the first electrode and a second throughconnecting to the second electrode; depositing a resistive material onthe layer of insulating material over the portion of the surface of thesubstrate between the first electrode and the second electrode and inthe plurality of through holes; and patterning the resistive material toform a plurality of resistors, the plurality of resistors comprising afirst resistor connecting the first electrode to the second electrodeand disposed on the insulating material extending over the portion ofthe surface of the substrate between the first electrode and the secondelectrode.
 22. The method of claim 21, wherein forming the plurality ofelectrodes comprises forming a plurality of concentric ring electrodes.23. The method of claim 22, wherein forming the plurality of concentricring electrodes comprises forming a first concentric ring electrodeseparated from a second concentric ring electrode by a gap of less thanabout 3 microns.
 24. The method of claim 22, wherein forming theplurality of concentric ring electrodes comprises forming a concentricring electrode having a constant width.
 25. The method of claim 21,wherein depositing the resistive material comprises depositing materialhaving a sheet resistance higher than a sheet resistance of theplurality of electrodes.
 26. The method of claim 21, wherein patterningthe resistive material to form the plurality of resistors comprisesforming at least one resistor having a resistance of at least about 2.5MΩ.
 27. The method of claim 21, wherein patterning the resistivematerial to form the plurality of resistors comprises forming at leastone resistor having a length-to-width ratio of about 25:1.
 28. Themethod of claim 21, wherein patterning the resistive material to formthe plurality of resistors comprises forming a first resistor with afirst width and a second resistor segment with a second width greaterthan the first width.
 29. The method of claim 21, wherein patterning theresistive material to form the plurality of resistors comprises forminga first resistor with a first length and a second resistor with a secondlength greater than the first length.
 30. The method of claim 21,wherein patterning the resistive material to form the plurality ofresistors comprises forming at least one resistor with a curved edge.31. The method of claim 21, further comprising: forming a buss lineconnected to at least one electrode in the plurality of electrodes. 32.The method of claim 21, wherein the plurality of resistors has aresistivity of less than 200 Ω per square, the insulating material has aresistivity of at least 10¹⁸ Ω per meter, the resistive material has aresistivity of at least 0.1 MΩ/square.
 33. An electro-active contactlens comprising: a base optical element; an electro-active elementembedded within the base optical element, the electro-active elementcomprising: a plurality of electrodes comprising a first electrode and asecond electrode on a surface of a substrate; an insulating layerdisposed on the plurality of electrodes and on a portion of the surfaceof the substrate between the first electrode and the second electrode;and a resistive bridge disposed on the insulating layer on the portionof the surface of the substrate between the first electrode and thesecond electrode, the resistive bridge connecting the first electrode inthe plurality of electrodes with the second electrode in the pluralityof electrodes via holes patterned into the insulating layer.
 34. Theelectro-active contact lens of claim 33, wherein the resistive bridgehas a resistance of at least about 2.5 MΩ.